Semiconductor device and method for manufacturing the same

ABSTRACT

An object of the present invention is to increase adhesiveness between thin films, particularly a high molecular film formed on an insulating surface, and the present invention provides a semiconductor device with high reliability and a method for manufacturing the semiconductor device with high yield. A semiconductor device of the present invention comprises a laminate structure formed in close contact with an organic insulating film on a hydrophobic surface of an inorganic insulating film including silicon and nitrogen. A film having the hydrophobic surface is an insulating film having a contact angle of water of equal to or more than 30°, preferably of equal to or more than 40°.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor device that is a devicethat can function by using semiconductor characteristics (for example, adisplay device, a semiconductor circuit, and electronics) and to amethod for manufacturing the semiconductor device.

2. Related Art

A liquid crystal molecule, a pixel electrode, a light-emitting layer,and the like which are display-related parts are laminated over aninterlayer film. Therefore, the interlayer film is required to have asmooth surface to prevent an orientation defect of liquid crystalmolecules, an inhomogeneous electric field, a minute defect of alight-emitting layer due to unevenness of a pixel electrode, and thelike.

An organic insulating film is used as the interlayer film over aninorganic insulating film because of its good smoothness (for instance,Reference 1: Japanese Unexamined Patent Publication No. Hei10-48607). Anorganic insulating film has advantage of being formed easily and that afilm thickness thereof can be set comparatively freely.

However, when an organic insulating film is used for a planarizationfilm, adhesiveness with an underlying layer film to be laminated becomesa problem depending on a combination of materials. In the case of pooradhesiveness, film peeling is caused. Such the semiconductor device hasa low reliability and is manufactured with a lower yield.

SUMMARY OF THE INVENTION

It is an object of the present invention to improve the adhesivenessbetween thin films, particularly the adhesiveness of an organicinsulating film to be formed on an insulating surface. The presentinvention provides a semiconductor device with high reliability and amethod for manufacturing the semiconductor device with a high yield.

A semiconductor device of the present invention has a laminate structurein which an organic insulating film is formed in close contact with ahydrophobic surface of an inorganic insulating film including siliconand nitrogen. Therefore, considering a semiconductor layer side as abottom, the inorganic insulating film may be laminated either below orabove the organic insulating film, and a surface in contact with theorganic insulating film has only to be hydrophobic.

In addition, a semiconductor device of the present invention comprisesan inorganic insulating film on a semiconductor layer, having ahydrophobic surface and including silicon and nitrogen and an organicinsulating film formed in close contact with the hydrophobic surface ofthe inorganic insulating film.

Besides, a semiconductor device of the present invention comprises afirst inorganic insulating film, a second inorganic insulating filmhaving a hydrophobic surface and including silicon and nitrogen on thefirst inorganic insulating film, and an organic insulating film formedin close contact with a hydrophobic surface of the second inorganicinsulating film, over a semiconductor film.

As for the inorganic insulating film, a surface thereof is hydrophilizedby a step such as hydrogenation by heating. Therefore, the secondinorganic insulating film having a hydrophobic surface may be formed onthe first inorganic insulating film hydrophilized by hydrorgenation. Atthat time, hydrogen concentration in the first inorganic insulating filmis lowered since hydrogen is released by hydrogenation. Thus, hydrogenconcentration in the second inorganic insulating film becomes higherthan that in the first inorganic insulating film.

A method for manufacturing the semiconductor device of the presentinvention comprises the steps of: forming a first inorganic insulatingfilm on a semiconductor layer; heat-treating at a temperature of from400° C. to 500° C.; forming a second inorganic insulating film having ahydrophobic surface and including silicon and nitrogen on the firstinorganic insulating film; and forming an organic insulating film on thesecond inorganic insulating film.

In addition, a method for manufacturing the semiconductor device of thepresent invention comprises the steps of: forming a first inorganicinsulating film containing hydrogen on a semiconductor layer; reducing ahydrogen content of the first inorganic insulating film by heat-treatingat a temperature of from 400° C. to 500° C.; forming the secondinorganic insulating film having a hydrophobic surface and includingsilicon and nitrogen on the first inorganic insulating film; and formingan organic insulating film on the second inorganic insulating film.

Since hydrogenation of the semiconductor layer by heating is caused byentry of hydrogen inside the first inorganic insulating film into thesemiconductor layer, hydrogen is released from the first inorganicinsulating film by heating, and a hydrogen content in the firstinorganic insulating film is lowered. This step is a step of terminatinga dangling bond of the semiconductor layer by hydrogen contained in thefirst inorganic insulating film.

As described above, the second inorganic insulating film having ahydrophobic surface can be formed on the first inorganic insulating filmhydrophilized by the step of hydrogenation. Since the organic insulatingfilm has good adhesiveness to a hydrophobic surface, the organicinsulating film can be formed on the second inorganic insulating filmhaving a hydrophobic surface, thereby laminating the film with goodadhesiveness.

In the present invention, the hydrophobic surface means a surface havinga wide contact angle of water, and an insulating surface preferablyhaving a contact angle of equal to or more than 30°, more preferablyequal to or more than 40°. Specifically, silicon nitride (SiN), siliconcarbide (SiC), and the like can be used for the (first or second)inorganic insulating film.

In the present invention, a silicon oxynitride (SiON) film includes Siof from 25 atom % to 35 atom %, oxygen of from 55 atom % to 65 atom %,nitrogen of from 1 atom % to 20 atom %, and hydrogen of 0.1 atom % to 10atom % is shown. A silicon nitride oxide (SiNO) film includes Si of from25 atom % to 35 atom %, oxygen of from 15 atom % to 30 atom %, nitrogenof from 20 atom % to 35 atom %, and hydrogen of from 15 atom % to 25atom %.

The (first or second) inorganic insulating film used in the presentinvention may be an inorganic insulating film including oxygen. And theinorganic insulating film preferably has nitrogen concentration of atleast 25 atom % or oxygen concentration of at most 25 atom %.Specifically, a silicon nitride oxide (SiON) film can be used.

The hydrophobic surface may be formed by nitrogen plasma treatment orfluorine plasma treatment with a non-depositional gas. As for thenon-depositional gas, N₂O, N₂, NH₃, F₂, CF₄, SiF₄, or the like can beused.

In the present invention, as the organic insulating film, a filmcomprising one kind of or a plurality kinds of organic resin materialsselected from acrylic resin, polyamide, or polyimide of photosensitiveor nonp.hotosensitive, for example, is used. The organic insulating filmmay be an insulating film including an organic material or an inorganicsubstance including an organic material. For instance, the organicinsulating film can be formed of an inorganic siloxane material and anorganosiloxane material substituted for hydrogen bonded silicon by anorganic radical such as methyl and phenyl including a Si—O—Si bond amongcompounds comprising silicon, oxygen, and hydrogen formed by using asiloxane material as a starting material.

The semiconductor device of the present invention has a film having ahydrophobic surface below the organic insulating film, thereby improvingthe adhesiveness and not causing film peeling. Therefore, thesemiconductor device of the present invention has high reliability andthe semiconductor device can be manufactured with high yield.

By applying the present invention, the following effect and the like canbe obtained.

The present invention prevents film peeling by forming the insulatingfilm having a hydrophobic surface below the organic insulating film tobe used as the interlayer film to improve the adhesiveness of thesefilms. Therefore, according to the present invention, a semiconductordevice having high reliability can be manufactured with high yield.

These and other objects, features and advantages of the presentinvention will become more apparent upon reading of the followingdetailed description along with the accompanied drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIGS. 1A to 1C shows a structure of the present invention;

FIGS. 2A and 2B shows a conventional structure;

FIGS. 3A to 3C are cross-sectional views showing a step of manufacturingan active matrix substrate;

FIGS. 4A and 4B are cross-sectional views showing a step ofmanufacturing an active matrix substrate;

FIG. 5 is a cross-sectional view of an active matrix substrate;

FIG. 6 shows an example of a semiconductor device of the presentinvention;

FIGS. 7A to 7F show examples of semiconductor devices;

FIGS. 8A to 8D show examples of semiconductor devices;

FIGS. 9A to 9C show examples of semiconductor devices; and

FIG. 10 is a cross-sectional view of an active matrix substrate.

DETAILED DESCRIPTION OF THE INVENTION

[Embodiment]

Although the present invention has been fully described by way ofexample with reference to the accompanying drawings, it is to beunderstood that various changes and modifications will be apparent tothose skilled in the art. Therefore, unless otherwise such changes andmodifications depart from the scope of the present invention hereinafterdefined, they should be construed as being included therein. Note that,in a structure of the present invention to be described hereinafter, thesame reference numbers are used for devices or portions that have thesame function. Descriptions about the same reference numbers areomitted.

The present invention is shown in FIGS. 1A to 1C. As shown in FIG. 1A, abase film 102 is formed on a substrate 101, and a semiconductor film 103is formed on the base film 102. For the substrate 101 over which thesemiconductor film 103 is formed, a glass substrate, a quartz substrate,a plastic substrate, a metal substrate, a flexible substrate, or thelike can be used. As the glass substrate, a substrate made of glass suchas barium borosilicate glass or aluminoborosilicate glass is given. Theflexible substrate is a film-shaped substrate made of PET, PES, PEN,acrylic, and the like. When a semiconductor device is manufactured withthe use of the flexible substrate, weight saving is anticipated.Preferably, a barrier layer such as an aluminum film (AlON, MN, AlO, orthe like), a carbon film (DLC (diamond like carbon), or the like), andSiN is preferably formed to be single-layered or multilayered on a topsurface or top and rear surfaces of the flexible substrate, therebyimproving durability, and the like.

The base film 102 is typically formed of a material selected fromsilicon nitride (referred to as SiN), silicon oxide (referred to asSiO₂), silicon nitride oxide (referred to as SiNO), aluminum nitride(referred to as AlN), aluminum oxynitride having more oxygen contentthan nitrogen content (referred to as AlON), aluminum nitride oxidehaving more nitrogen content than oxygen content (referred to as AlNO),or aluminum oxide (referred to as AlO). The base film may have atwo-layer structure, and may have a single layer structure or a laminatestructure with more than two layers.

An aluminum oxynitride (AlON) film including Al of from 30 atom % to 40atom %, oxygen of from 50 atom % to 70 atom %, nitrogen of from 1 atom %to 20 atom % may be used as the aluminum oxynitride film. An aluminumnitride oxide (AlNO) film including Al of from 30 atom % to 50 atom %,oxygen of from 30 atom % to 40 atom %, nitrogen of from 10 atom % to 30atom % also may be used as the aluminum nitride oxide film.

There is no particular limitation of a material of the semiconductorfilm 103; however, the semiconductor film may be formed of silicon or asilicon germanium (SiGe) alloy. As for the semiconductor film 103, anamorphous semiconductor film, a microcrystal semiconductor film, acrystalline semiconductor film, and the like are given, and a compoundsemiconductor film having an amorphous structure such as an amorphoussilicon germanium film and an amorphous silicon carbide film may beapplied.

An amorphous semiconductor (typically, hydrogenated amorphous silicon)or a crystalline semiconductor (typically, polysilicon) is used as amaterial of the semiconductor film. Polysilicon includes so-calledhigh-temperature polysilicon using polycrystalline silicon formedthrough a process temperature of equal to or more than 800° C. as itsmain component, so-called low-temperature polysilicon usingpolycrystalline silicon formed through a process temperature of lessthan or equal to 600° C. as its main component, crystalline siliconcrystallized by adding an element for promoting crystallization, and thelike.

As other materials, a semi-amorphous semiconductor or a semiconductorincluding a crystal phase in a part of the semiconductor film can beused. The semi-amorphous semiconductor is a semiconductor having anintermediate structure between an amorphous structure and a crystallinestructure (including a single crystal and a polycrystal) and a thirdcondition that is stable in terms of free energy, and is a crystallinesemiconductor having short-distance order and lattice distortion.Typically, the semi-amorphous semiconductor is a semiconductor havingsilicon as a main component wherein Raman spectrum is shifted to a lowerwavenumber side than 520 cm⁻¹ with lattice distortion. Further, thesemiconductor includes hydrogen or halogen of at least 1 atom % or moreas a neutralizing agent of a dangling bond. Here, the semiconductor isreferred to as a semi-amorphous semiconductor (hereinafter, referred toas a “SAS”). The SAS is also referred to as a so-called microcrystalsemiconductor (typically, microcrystal silicon).

The SAS is obtained by grow discharge decomposition (plasma CVD) of asilicide gas. A typical silicide gas is SiH₄, and the other gases suchas Si₂H₆, SiHCl₃, SiCl₄, SiF₄, or the like can be used instead. Inaddition, GeF₄ or F₂ may be mixed with each of the above gases. The SAScan be formed easily with the use of the silicide gas diluted withhydrogen or one kind of or plural kinds of noble gas elements selectedfrom hydrogen, helium, argon, krypton, and neon. A dilution ratio ofhydrogen to the silicide gas is preferably set from 2 to 1000 times in aflow ratio, for example. Of course, the formation of the SAS by the growdischarge decomposition is preferably performed under reduced pressure;however, discharge at atmospheric pressure also can be applied to formthe SAS. Typically, the formation of the SAS may be performed within apressure range of from 0.1 Pa to 133 Pa. A power supply frequency toform glow discharge is set at from 1 MHz to 120 MHz, preferably from 13MHz to 60 MHz. High-frequency power may be set appropriately. Asubstrate heating temperature is preferably at equal to or less than300° C., and the SAS can be formed at a substrate heating temperature offrom 100° C. to 200° C. Here, as an impurity element taken in mainly atthe time of film formation, impurities in atmospheric constituents suchas oxygen, nitrogen, and carbon are preferably set at equal to or lessthan 1×10²⁰ cm⁻³. Specifically, oxygen concentration is preferably setat equal to or less than 5×10¹⁹ cm⁻³, more preferably equal to or lessthan 1×10¹⁹ cm⁻³. Stability is increased by further promoting latticedistortion with a noble gas element such as helium, argon, krypton, andneon included in the SAS to obtain a favorable SAS. A SAS layer formedwith a fluorinated gas may be laminated with a SAS layer formed with ahydrogenated gas as a semiconductor layer.

Subsequently, a gate insulating film 104 covering the semiconductor film103 is formed. Materials of the above-described base film 102 may beused for the gate insulating film 104. The gate insulating film 104 isnot limited to a single layer, and a laminated layer with plural kindsof insulating films selected from the above-described materials.

Subsequently, a conductive film 106 to be a gate electrode is formed onthe gate insulating film. The conductive film 106 may be formed of anelement selected from Ta, W, Ti, Mo, Al, Cu or an alloy material or acompound material having the foregoing element as a main component. Asthe conductive film 106, a semiconductor film represented bypolycrystalline silicon film doped with an impurity element such asphosphorus or an AgPdCu alloy may be used. In addition, a two-layerstructure may be employed without limiting to a single layer structure,and, for example, a three-layer structure sequentially laminated with atungsten film, an alloy film of aluminum and silicon (Al—Si), and atitanium nitride film may be employed.

Subsequently, a first inorganic insulating film 105 is formed. Besides,a step of hydrogenating the semiconductor layer is performed byheat-treating at from 300° C. to 550° C. for from 1 to 12 hours in anitrogen atmosphere. The step is preferably performed at a temperatureof from 400° C. to 500° C. The step is a step of terminating danglingbonds of the semiconductor layers by hydrogen contained in the firstinorganic insulating film 105. Since the hydrogenation is caused byentry of hydrogen in the first inorganic insulating film into thesemiconductor layer, hydrogen is released from the first inorganicinsulating film, and the hydrogen concentration in the first inorganicinsulating film is lowered.

The first inorganic insulating film 105 is formed of a material selectedfrom silicon nitride, silicon oxide, silicon nitride oxide having morenitrogen content than oxygen content (SiNO), aluminum nitride (MN),aluminum oxynitride having more oxygen content than nitrogen content(AlON), or aluminum nitride oxide having more nitrogen content thanoxygen content (AlNO), or aluminum oxide.

Before and after the heat treatment, wettability of an insulating filmused for the first inorganic insulating film 105 changes. For instance,a silicon nitride film has a contact angle of water of 50° and ishydrophobic after film formation, but the film has a contact angle of20°, and becomes hydrophilic after hydrogenation.

Thus, due to the treatment performed in a step of manufacturing, asurface of a thin film becomes hydrophilic. Although an organicinsulating film 207 is formed on a hydrophilized first inorganicinsulating film 205 as shown in FIGS. 2A and 2B, the adhesiveness is sopoor that a defect such as film peeling is caused.

Therefore, in the present invention, a second inorganic insulating film108 having a hydrophobic surface is formed on the first inorganicinsulating film 105 after hydrogenation as shown in FIG. 1B. The secondinorganic insulating film is a film having a hydrophobic surface. Thehydrophobic surface means a surface having a wide contact angle ofwater, and an insulating surface preferably having a contact angle ofequal to or more than 30°, more preferably equal to or more than 40°. Asfor a film having the insulating surface (insulating film), an inorganicinsulating film including nitrogen or carbon, or nitrogen and oxygen maybe used. Specifically, silicon nitride (SiN), silicon nitride oxidehaving more nitrogen content than oxygen content (SiNO), silicon carbide(SiC), or the like can be used.

Since the second inorganic insulating film 108 used in the presentinvention is not heated as the first inorganic insulating film 105, thesecond inorganic insulating film 108 has higher concentration ofcontained hydrogen than the first inorganic insulating film 105.

In the case of using an inorganic insulating film including nitrogen andoxygen as the film having the hydrophobic surface (the second inorganicinsulating film) used in the present invention, the inorganic insulatingfilm is preferably an inorganic insulating film having nitrogenconcentration in the inorganic insulating film of equal to or more than25 atom % or oxygen concentration in the film of less than or equal to25 atom %. Specifically, a silicon nitride oxide (SiNO) film havingnitrogen concentration of equal to or more than 25 atom % or oxygenconcentration of less than or equal to 25 atom % can be used.

In the present invention, a silicon oxynitride (SiON) film denotes afilm including Si of from 25 atom % to 35 atom %, oxygen of from 55 atom% to 65 atom %, nitrogen of from 1 atom % to 20 atom %, hydrogen of 0.1atom % to 10 atom %. A silicon nitride oxide (SiNO) film denotes a filmincluding Si of from 25 atom % to 35 atom %, oxygen of from 15 atom % to30 atom %, nitrogen of from 20 atom % to 35 atom %, and hydrogen of from15 atom % to 25 atom %.

The hydrophobic surface may be formed by nitrogen plasma treatment orfluorine plasma treatment with a non-depositional gas. As for thenon-depositional gas, N₂O, N₂, NH₃, F₂, CF₄, SiF₄, or the like can beused.

An organic insulating film 107 that is an interlayer film and is made ofan organic insulating material is formed on the second inorganicinsulating film 108. As the organic insulating film 107, a filmcomprising one kind of or plural kinds of organic resin materialsselected from acrylic resin, polyamide, or polyimide of photosensitiveor nonphotosensitive, for example, can be used.

As shown in FIG. 1C, the present invention prevents film peeling byforming an insulating film having a hydrophobic surface below theorganic insulating film to be used as the interlayer film to improveadhesiveness of these films. Therefore, according to the presentinvention, a semiconductor device with high reliability can bemanufactured with high yield.

EXAMPLE 1

In this example, focusing attention on a property of materials of anorganic insulating film and a base film in contact with a bottom surfaceof the organic insulating film, particularly on wettability, arelationship between the property and the adhesiveness was derived froman experiment.

In this example, two types of samples were created by forming a siliconnitride film (SiN) and a silicon nitride oxide film (SiNO) on eachsubstrate as base films. As the substrate, a substrate with aninsulating film formed on a surface of a glass substrate, a quartzsubstrate, a silicon substrate, a metal substrate, or a stainlesssubstrate may be used. In this example, the glass substrate was used.

In this example, the silicon nitride film (SiN) was formed to be 100 nmin thickness on the glass substrate by plasma CVD (SiN original sample).In addition, the silicon nitride oxide film (SiNO) was also formed to be100 nm in thickness on the glass substrate by plasma CVD (SiNO originalsample). Nitrogen concentration of the silicon nitride oxide film (SiNO)of this example was 34 atom %, and oxygen concentration was 14 atom %.

Subsequently, each sample was processed to form six types of samples:samples which were processed by hydrofluoric acid treatment for 120seconds (sample names: SiN(a) and SiNO(a); samples which were processedby hydro washing for 60 seconds and by hydrofluoric acid treatment for120 seconds (sample names: SiN(b) and SiNO(b); and the SiN originalsample and the SiNO original sample without any treatment (sample names:SiN(c) and SiNO(c). Then, all of the six types of samples were washedwith water, and the water was vaporized by heating at a temperature of150° C. for three minutes.

Subsequently, an organic insulating film was formed on six types ofsamples processed by each treatment. In this example, the organicinsulating film was formed by applying a positive photosensitive acrylicresin. Thereafter, peripheries of all the samples were washed, and then,all the samples were exposed to light and developed.

An evaluation of the above-described six types of samples, sample names:the SiN(a); the SiN(b); the SiN(c); the SiNO(a); the SiNO(b); and theSiNO(c); was conducted. Treatment steps and evaluation results of eachsample in this example are shown in Table 1.

[Table 1]

Water contact angles of surfaces of the SiN original sample and the SiNOoriginal sample after the deposition and before each treatment weremeasured with a contact angle measuring instrument. In addition,wettability after the application of the positive photosensitive acrylicresin and adhesiveness of patterns after the development were observed.As for the wettability after the application of an acrylic resin, thecase of having had poor wettability and having had some areas that isnot covered with the acrylic resin is shown as “x”, and the case withoutany defect is shown as “o”. As for pattern adhesiveness after thedevelopment, the case that a defect such as film peeling was observed isshown as “x”, and the case without any defect is shown as “o”.

As shown in Table 1, the silicon nitride films (SiN) showed goodwettability after the application of the positive photosensitivityacrylic resin and good pattern adhesiveness with no defect after thedevelopment in all of the three samples: the SiN(a); the SiN(b); and theSiN(c). The silicon nitride oxide films (SiNO) showed good wettabilityin the SiNO(a), the SiNO(b) processed with the hydrofluoric acidtreatment; however, the adhesiveness of patterns after the developmentwas so poor that the patterns was removed. However, the SiNO(c) showedgood wettability, and pattern peeling after the development did notoccur.

On the other hand, as the results of the water contact anglemeasurement, a contact angle of the silicon nitride film (SiN) was 50°and that of the silicon nitride oxide film was 44°. The wider thecontact angle of water was, the more hydrophobic the surface was againstwater. Therefore, it was found that both of the silicon nitride film(SiN) and the silicon nitride oxide film (SiNO) were hydrophobic, andthe silicon nitride film (SiN) was further hydrophobic. It can be saidthat the more hydrophobic the film surface was, the better theadhesiveness with the organic insulating film was.

Consequently, it was confirmed that the film having hydrophobic surfacesuch as the silicon nitride film (SiN) or the silicon nitride oxide film(SiNO) used in this example had good adhesiveness with the organicinsulating film such as the acrylic resin.

COMPARATIVE EXAMPLE

As a comparative example, adhesiveness in the case of forming an organicinsulating film by using a silicon oxynitride film (SiON) and a siliconoxide film (SiO₂) as a base film was evaluated.

The silicon oxynitride film (SiON) was formed to be 100 nm in thicknesson a glass substrate by plasma CVD (SiON original sample). In addition,a silicon oxide film (SiO₂) was also formed to be 100 nm in thickness ona glass substrate by plasma CVD (SiO₂ original sample). Nitrogenconcentration of the silicon oxynitride film (SiON) was 3 atom %, andoxygen concentration was 60 atom % in this comparative example.

Similarly to this example, after treating each of the SiON originalsample and the SiO₂ original sample, a positive photosensitive acrylicfilm was formed thereupon by application as an organic insulating film,and evaluations were conducted to each sample. Treatment steps andevaluation results of each sample: SiON(a); SiON(b); SiON(c); SiO₂(a);SiO₂(b); and SiO₂(c); in this comparative example are shown in Table 2.

[Table 2]

As shown in Table 2, all of the six types of the samples: the siliconoxynitride films: the SiON(a); the SiON(b); and the SiON(c); the oxidefilms: SiO₂(a); SiO₂(b); SiO₂(c); showed good wettability after theapplication of the positive photosensitive acrylic resin; however,adhesiveness of patterns after development was so poor that the patternswas removed.

On the other hand, as a result of water contact angle measurement, acontact angle of the silicon oxynitride film (SiON) was 24° and that ofthe silicon oxide film (SiO₂) was 15°. Surfaces of the siliconoxynitride film (SiON) and the silicon oxide film (SiO₂) used in thiscomparative example were hydrophilic, whereas the surfaces of thesilicon nitride film (SiN) and the silicon nitride oxide film (SiNO) inthis example were hydrophobic.

According to the above description, the film having the hydrophilicsurface was proved to have poor adhesiveness with the organic insulatingfilm, and the film having the hydrophobic surface was proved to havegood adhesiveness with the organic insulating film. Therefore, astructure wherein the organic insulating film was formed on theinsulating film having the hydrophobic surface can be said to be astructure with high reliability and having good adhesiveness.

EXAMPLE 2

In this example, a method for manufacturing an active matrix substrateusing the present invention is described with reference to FIGS. 3A to5. An active matrix substrate comprises a plurality of TFTs, but anactive matrix substrate comprising a drive circuit portion having ann-channel TFT and a p-channel TFT and a pixel portion having ann-channel TFT is described here.

A silicon nitride oxide film is formed on a substrate 300 having aninsulating surface as a base film 301 by plasma CVD to have a thicknessof from 10 nm to 200 nm (preferably, from 50 nm to 100 nm) and a siliconoxynitride film is laminated thereupon to have a thickness of from 50 nmto 200 nm (preferably, from 100 nm to 150 nm). In this example, thesilicon nitride oxide film of 50 nm and the silicon oxynitride film of100 nm are formed by plasma CVD. As the substrate 300, a glasssubstrate, a quartz substrate, a silicon substrate, a metal substrate,or a stainless substrate each of which has an insulating surface on asurface thereof may be used. In addition, a plastic substrate or aflexible substrate having enough heat resistance against a treatmenttemperature of this example may be used. Further, a two-layer structuremay be adopted, and a single layer film or a laminate structure havingmore than two layers of the base (insulating) film may also be adopted.

Subsequently, a semiconductor film is formed on the base film. Thesemiconductor film may be formed by a known technique (sputtering,LPCVD, plasma CVD, or the like) to have a thickness of from 25 nm to 200nm (preferably, from 30 nm to 150 nm). There is no particular limitationof a material of the semiconductor film; however, the semiconductor filmmay be preferably formed of silicon or a silicon germanium (SiGe) alloy.

In this example, an amorphous silicon film is formed as thesemiconductor film by plasma CVD to have a thickness of 54 nm. In thisexample, the amorphous silicon film is treated by thermalcrystallization and laser crystallization with the use of a metalelement for promoting crystallization; however, without introducing themetal element into the amorphous silicon film, hydrogen included in theamorphous silicon film may be released to lower hydrogen concentrationto 1×10²⁰ atoms/cm³ or less by heating in a nitrogen atmosphere at atemperature of 500° C. for one hour. Thereafter, the lasercrystallization may be performed. The dehydrogenation is performedbecause the amorphous silicon film is damaged by laser irradiation whenthe film contains much hydrogen.

Nickel is used as the metal element, and is doped into the amorphoussilicon film by solution application. There is no particular limitationof a method for doping the metal element into the amorphous silicon filmon condition that the metal element can exist on the surface of orinside the amorphous silicon film, and a method such as sputtering, CVD,plasma treatment (including plasma CVD), adsorption, or a method forapplying a metal salt solution can be employed. Among them, a methodusing a solution is simple and easy, and is useful for easily adjustingconcentration of the metal element. Further, at this time, an oxide filmis preferably formed by UV rays irradiation in an oxygen atmosphere,thermal oxidation, treatment with ozone water or hydrogen peroxideincluding hydroxyl radical, or the like in order to improve wettabilityof the surface of an amorphous semiconductor film and to spread watersolution over an entire surface of the amorphous silicon film.

Subsequently, a heat treatment is performed at a temperature of from500° C. to 550° C. for from 4 hours to 20 hours to crystallize theamorphous silicon film. In this example, after forming ametal-containing layer by solution application with the use of nickel asthe metal element and doping nickel into the amorphous silicon film,heat treatment is performed thereto at a temperature of 550° C. for fourhours, thereby obtaining a first crystalline silicon film.

Next, a second crystalline silicon film is obtained by irradiating thefirst crystalline silicon film with laser light to promotecrystallization. Laser crystallization is a method for irradiating thesemiconductor film with laser light. As for the laser, a solid-statelaser, a gas laser, or a metal laser of continuous wave oscillation ispreferable to be used. The solid-state laser includes a YAG laser, aYVO₄ laser, a YLF laser, a YAlO₃ laser, a glass laser, a ruby laser, analexandrite laser, a Ti:sapphire laser, and the like of continuous waveoscillation; the gas laser includes an Ar laser, a Kr laser, a CO₂laser, and the like of continuous wave oscillation; and the metal laserincludes a helium cadmium laser, a copper vapor laser, and a gold vaporlaser of continuous wave oscillation. An excimer laser of continuouslight emission can also be applied. The laser light may be converted toa harmonic by a non-linear optical device. A crystal used for thenon-linear optical device such as LBO, BBO, KDP, KTP, KB5, or CLBO hasadvantage of conversion efficiency. The conversion efficiency can bedrastically raised by introducing these non-linear optical devices intoa laser resonator. A laser of the harmonic is typically doped with Nd,Yb, Cr, or the like, and these are excited to oscillate a laser. A kindof the dopant may be selected appropriately. As for the semiconductorfilm, an amorphous semiconductor film, a microcrystal semiconductorfilm, a crystalline semiconductor film, and the like are given, and acompound semiconductor film having an amorphous structure such as anamorphous silicon germanium film, an amorphous silicon carbide film, orthe like may be applied.

Semiconductor layers 305 to 308 are formed by patterning the thusprovided crystalline semiconductor film with the use ofphotolithography.

After forming the semiconductor layers 305 to 308, a very small amountof an impurity element (boron or phosphorous) may be doped to control athreshold value of a TFT.

Subsequently, a gate insulating film 309 covering the semiconductorlayers 305 to 308 is formed. The gate insulating film 309 is formed ofan insulating film including silicon to have a thickness of from 40 nmto 150 nm by plasma CVD or sputtering. In this example, a siliconoxynitride film is formed to have a thickness of 115 nm by plasma CVD.The gate insulating film is not limited to the silicon oxynitride film,and other insulating films with a single layer structure or a laminatestructure may be used.

Subsequently, a first conductive film of a film thickness of from 20 nmto 100 nm and a second conductive film of a film thickness of from 100nm to 400 nm are formed and laminated over the gate insulating film. Thefirst conductive film and the second conductive film may be formed of anelement selected from Ta, W, Ti, Mo, Al, and Cu, or an alloy material ora compound material having the element as a main component. Asemiconductor film represented by a polycrystalline silicon film dopedwith an impurity element such as phosphorus or an AgPdCu alloy may beused as the first conductive film and the second conductive film.Without limited to a two-layer structure, a three-layer structure inwhich a tungsten film of 50 nm in thickness, an alloy (Al—Si) film ofaluminum and silicon of 500 nm in thickness, and a titanium nitride filmof 30 nm in thickness are laminated sequentially may be applied. In thecase of the three-layer structure, tungsten nitride may be used in placeof tungsten of the first conductive film; an alloy (Al—Ti) film ofaluminum and titanium may be used in place of an alloy (Al—Si) film ofaluminum and silicon of the second conductive film; or a titanium filmmay be used in place of a titanium nitride film of a third conductivefilm. Further, a single layer structure may be applied. In this example,a tantalum nitride film 310 of 30 nm in thickness and a tungsten film311 of 370 nm in thickness are sequentially laminated over the gateinsulating film 309 (FIG. 3A).

Next, a mask comprising a resist is formed by photolithography, and afirst etching treatment is performed to form an electrode and a wiring.The first conductive film and the second conductive film can be etchedinto a desired tapered shape by appropriately adjusting etchingconditions (such as electric energy applied to a coil-shaped electrode,electric energy applied to an electrode on a substrate side, andtemperature of the electrode on the substrate side) with the used of ICP(Inductively Coupled Plasma) etching. For an etching gas, achlorine-based gas typified by Cl₂, BCl₃, SiCl₄, or CCl₄; afluorine-based gas typified by CF₄, SF₆, or NF₃; or O₂ can be usedappropriately.

A first-shape conductive layer (a first conductive layer and a secondconductive layer) comprising a first conductive layer and a secondconductive layer is formed by the first etching treatment.

Subsequently, a second etching treatment is performed without removingthe mask comprising the resist. Here, a W film is etched selectively.Then, the second conductive layers 322 b to 326 b are formed by thesecond etching treatment. On the other hand, the first conductive layers322 a to 326 a are hardly etched, and second-shape conductive layers 322to 326 are formed (FIG. 3B).

An impurity element imparting n-type conductivity is added to thesemiconductor layer in low concentration by performing a first dopingtreatment without removing the mask comprising the resist. The dopingtreatment may be performed by ion doping or ion implantation. An elementbelonging to Group 15 in the periodic table, typically phosphorus (P) orarsenic (As) is used for the impurity element imparting n-typeconductivity, and phosphorus (P) is used here. In this case, thesecond-shape conductive layers 322 to 326 becomes a mask for preventingthe impurity element imparting n-type conductivity from being doped intothe semiconductor layer, and an impurity region is formed in aself-aligned manner. The impurity element imparting n-type conductivityis added to the impurity region in a concentration range of from 1×10¹⁸atoms/cm³ to 1×10²⁰ atoms/cm³.

Another mask comprising a resist is formed after removing the maskcomprising the resist, and a second doping treatment is performed at ahigher accelerating voltage than the first doping treatment. The dopingtreatment is performed by using the second conductive layers 323 b, 324b and 325 b as a mask for preventing the impurity element from dopinginto the semiconductor layer so as to add the impurity element to thesemiconductor layer below the tapered portion of the first conductivelayers 323 a, 324 a and 325 a. Subsequently, a third doping treatment isperformed at a lower accelerating voltage than the second dopingtreatment. According to the second doping treatment and the third dopingtreatment, a low concentration impurity regions 335 and 338 overlappingthe first conductive layer is added with the impurity element impartingn-type conductivity in a concentration range of from 1×10¹⁸ atoms/cm³ to5×10¹⁹ atoms/cm³, and high concentration impurity regions 334 and 337are added with the impurity element imparting n-type conductivity in aconcentration range of from 1×10¹⁹ atoms/cm³ to 5×10²¹ atoms/cm³.

The low concentration impurity region and the high concentrationimpurity regions can be formed by one doping treatment of the seconddoping treatment and the third doping treatment by setting anaccelerating voltage appropriately.

Subsequently, yet another mask comprising a resist is formed afterremoving the mask comprising the resist, and a fourth doping treatmentis performed. According to the fourth doping treatment, impurity regions343, 344, 347, and 348 which are added with an impurity elementimparting an opposite conductivity type to the conductivity type of thepreviously added impurity element to a semiconductor layer to be anactive layer of a p-channel TFT are formed. The impurity regions areformed in a self-aligned manner by using the second conductive layers322 b and 326 b as masks for preventing the impurity element from dopinginto the semiconductor layer and by adding an impurity element impartingp-type conductivity. In this example, the impurity regions 343, 344,347, and 348 are formed by ion doping using diborane (B₂H₆). In the caseof the fourth doping treatment, a semiconductor layer forming ann-channel TFT is covered with the mask comprising the resist. Accordingto the first to third doping treatments, the impurity regions are dopedwith phosphorus in different concentrations respectively. However,problems do not arise because the impurity regions function as a sourceregion and a drain region of a p-channel TFT by doping so as to have aconcentration of an impurity element imparting p-type conductivity offrom 1×10¹⁹ atoms/cm³ to 5×10²¹ atoms/cm³.

According to the above-described steps, the impurity regions are formedin each semiconductor layer (FIG. 3C).

Subsequently, the mask comprising the resist is removed, and a firstinsulating film 349 is formed as a passivation film. The firstinsulating film 349 is formed of an insulating film including silicon tobe from 100 nm to 200 nm in thickness by plasma CVD or sputtering (FIG.4A). The first insulating film 349 is not limited to the siliconoxynitride film, and other insulating films including silicon and havinga single layer structure or a laminate structure may be adopted. In thisexample, a silicon nitride film of 150 nm in thickness is formed byplasma CVD.

Moreover, a step of hydrogenating a semiconductor layer is performed byheat-treating at from 300° C. to 550° C. for from 1 hour to 12 hours ina nitrogen atmosphere. The step is preferably performed at a temperatureof from 400° C. to 500° C. The step is a step of terminating danglingbonds of the semiconductor layers by hydrogen contained in the firstinsulating film 349. In this example, the heat treatment is performed at410° C. for one hour. Since the hydrogenation is caused by entry ofhydrogen in the first insulating film into the semiconductor layer,hydrogen is released from the first insulating film, and hydrogencontent in the first insulating film is reduced.

The first insulating film 349 is formed of a material selected fromsilicon nitride, silicon oxide, silicon oxynitride having more oxygencontent than nitrogen content (SiON), silicon nitride oxide (SiNO),aluminum nitride (AlN), aluminum oxynitride having more oxygen contentthan nitrogen content (AlON), aluminum nitride oxide having morenitrogen content than oxygen content (AlNO), and aluminum oxide.

Before and after the heat treatment, wettability of an insulating filmused for the first insulating film 349 changes. For instance, a siliconnitride film used in this example has a contact angle of water of 50°and is hydrophobic after film formation, but the film has a contactangle of 20° after hydrogenation, and becomes hydrophilic.

Thus, due to the treatment performed in a step of manufacturing, asurface of a thin film becomes hydrophilic. Although an organicinsulating film to be an interlayer film is formed on a hydrophilizedfirst insulating film 349, a defect such as film peeling is caused dueto poor adhesiveness.

Therefore, in the present invention, as shown in FIG. 4B, a secondinsulating film 351 is formed on the first insulating film 349 afterhydrogenation. The second insulating film is a film having a hydrophobicsurface. The hydrophobic surface means a surface having a wide contactangle of water, and an insulating surface preferably having a contactangle of equal to or more than 30°, more preferably equal to or morethan 40°. As for a film having an insulating surface (insulating film),a film including an inorganic material, or an inorganic insulating filmincluding nitrogen or carbon, or nitrogen and oxygen may be used.Specifically, silicon nitride (SiN), silicon nitride oxide having morenitrogen content than oxygen content (SiNO), silicon carbide (SiC), orthe like can be used.

Since the second insulating film 351 in the present invention is notheated as the first insulating film 349 and hydrogen is not released,the second insulating film has higher concentration of containedhydrogen than the first insulating film 349.

In the case of using an inorganic insulating film including nitrogen andoxygen as the film having the hydrophobic surface (the second insulatingfilm) 351 used in the present invention, the inorganic insulating filmis preferably an inorganic insulating film having nitrogen concentrationin the organic insulating film of equal to or more than 25 atom % oroxygen concentration in the film of less than or equal to 25 atom %.Specifically, a silicon nitride oxide (SiNO) film having nitrogenconcentration of equal to or more than 25 atom % or oxygen concentrationof less than or equal to 25 atom % can be used.

In the present invention, a silicon oxynitride (SiON) film denotes afilm including Si of from 25 atom % to 35 atom %, oxygen of from 55 atom% to 65 atom %, nitrogen of from 1 atom % to 20 atom %, and hydrogen offrom 0.1 atom % to 10 atom %. A silicon nitride oxide (SiNO) filmdenotes a film including Si of from 25 atom % to 35 atom %, oxygen offrom 15 atom % to 30 atom %, nitrogen of from 20 atom % to 35 atom %,and hydrogen of from 15 atom % to 25 atom %.

The hydrophobic surface may be formed by nitrogen plasma treatment orfluorine plasma treatment with a non-depositional gas. As for thenon-depositional gas, N₂O, N₂, NH₃, F₂, CF₄, SiF₄, or the like can beused.

Before forming the second insulating film 351, heat-treatment,irradiation of intense light, or irradiation of laser light may becarried out in order to activate the impurity element. Simultaneouslywith the activation, plasma damage of the gate insulating film or of theinterface between the gate insulating film and the semiconductor layercan be repaired.

An organic insulating film 350 that is an interlayer film and is made ofan organic insulating material is formed on the second insulating film351. As the organic insulating film 350, a film comprising one kind ofor plural kinds of organic resin materials selected from acrylic resin,polyamide, or polyimide of photosensitive or nonphotosensitive, forexample, can be used. In this example, a positive photosensitive acrylicfilm having a film thickness of 1.6 μm is formed. However, the filmthickness may be determined appropriately in the range of from 1 μm to 2μm. Thereafter, a passivation film comprising a nitride insulating film(typically, a silicon nitride film, a silicon nitride oxide film, or acarbon nitride film (CN)) may be formed on the organic insulating film350.

Thus, the present invention prevents film peeling by forming aninsulating film having a hydrophobic surface below an organic insulatingfilm to be used as an interlayer film to improve the adhesiveness ofthese films. Therefore, according to the present invention, asemiconductor device with high reliability can be manufactured with highyield.

Subsequently, a metal film is formed and etched to form a sourceelectrode, a drain electrode, and each wiring (not shown) forelectrically connecting to each impurity region. A film comprising anelement of aluminum (Al), titanium (Ti), molybdenum (Mo), tungsten (W),or silicon (Si) or an alloy film with the use of these elements may beused for the metal film. In this example, after laminating a titaniumfilm/a titanium-aluminum alloy film/a titanium film (Ti/Al—Si/Ti) to be100 nm/350 nm/100 nm in thickness respectively, a source electrode, adrain electrode 352 and each wiring (not shown) are formed by patterningand etching the laminated film into a desired shape.

Then, an electrode (an anode or a cathode in an EL display device, or anpixel electrode in a liquid crystal display device) is formed. For theelectrode, a transparent conductive film such as ITO or SnO₂, or a metalfilm such as Al in the case of a reflective liquid crystal displaydevice may be used. In this example, an electrode 353 is formed byforming ITO and etching the ITO into a desired shape (FIG. 5).

According to the above-described steps, an active matrix substratecomprising a TFT is completed.

Not limited to a method for manufacturing a TFT described in thisexample, the present invention can be applied to a top gate type (planartype), a bottom gate type (inversely staggered type), or a dual gatetype having two gate electrodes disposed above and below a channelregion with a gate insulating film therebetween.

The present invention prevents a defect such as film peeling by formingan insulating film having a hydrophobic surface below the organicinsulating film to be used as the interlayer film to improve theadhesiveness of these films. Therefore, according to the presentinvention, a semiconductor device with high reliability can bemanufactured with high yield.

EXAMPLE 3

In this example, an example of using a bottom gate type thin filmtransistor (specifically, an inversely staggered type TFT) as a thinfilm transistor in Example 2 is described. Namely, the present inventioncan be applied even if the inversely staggered type TFT is used as aswitching TFT and/or a driving TFT in Example 2.

This example is described with reference to FIG. 10. In FIG. 10,conductive layers 801 to 804 to be gate electrodes, a gate insulatingfilm 805, and semiconductor layers 806 to 809 having impurity regionsare formed over a substrate 800. In this example, since a material and aformation method are similar to Example 2, a detailed description is notdone here, and Example 2 may be referred to.

After forming a first insulating film 810 over the semiconductor layers806 to 809, the semiconductor layers 806 to 809 are hydrogenated byheat-treating at a temperature of 410° C. for one hour in a nitrogenatmosphere. Dangling bonds of the semiconductor layers are terminated byhydrogenation. Since the hydrogenation is caused by entry of hydrogen inthe first insulating film into the semiconductor layers, hydrogen isreleased from the first insulating film 810 and hydrogen concentrationin the first insulating film 810 is lowered.

The first insulating film 810 is formed of a material selected fromsilicon nitride, silicon oxide, silicon oxynitride having more oxygencontent than nitrogen content (SiON), silicon nitride oxide (SiNO),aluminum nitride (AlN), aluminum oxynitride having more oxygen contentthan nitrogen content (AlON), aluminum nitride oxide having morenitrogen content than oxygen content (AlNO), or aluminum oxide.

Before and after the heat treatment, wettability of an insulating filmused for the first insulating film 810 changes. For instance, a siliconnitride film used in this example has a contact angle of water of 50°and is hydrophobic after film formation, but the film has a contactangle of 20° after hydrogenation, and becomes hydrophilic.

Thus, due to the treatment performed in a step of manufacturing, a/thesurface of a thin film becomes hydrophilic. Although an organicinsulating film is formed on a hydrophilized first insulating film 810,a defect such as film peeling is caused due to poor adhesiveness.

Therefore, in the present invention, a second insulating film 811 isformed on the first insulating film 810 after hydrogenation. The secondinsulating film is a film having a hydrophobic surface. The hydrophobicsurface means a surface having a wide contact angle of water, and aninsulating surface preferably having a contact angle of equal to or morethan 30°, more preferably equal to or more than 40°. As for a filmhaving an insulating surface (insulating film), an inorganic insulatingfilm, for instance, an inorganic insulating film including nitrogen,carbon, or nitrogen and oxygen may be used. Specifically, siliconnitride (SiN), silicon nitride oxide having more nitrogen content thanoxygen content (SiNO), silicon carbide (SiC), or the like can be used.

Since the second insulating film 811 used in the present invention isnot heated as the first insulating film 810, the second insulating filmhas more hydrogen content and higher hydrogen concentration than thefirst insulating film 810.

In the case of using an inorganic insulating film including nitrogen andoxygen as the film having the hydrophobic surface (the second insulatingfilm) 811 used in the present invention, the inorganic insulating filmis preferably an inorganic insulating film having nitrogen concentrationin the inorganic insulating film of equal to or more than 25 atom % orthe one having oxygen concentration in the film of less than or equal to25 atom %. Specifically, a silicon nitride oxide (SiNO) film havingnitrogen concentration of equal to or more than 25 atom % or oxygenconcentration of less than or equal to 25 atom % can be used.

In the present invention, a silicon oxynitride (SiON) film denotes asilicon oxynitride film including Si of from 25 atom % to 35 atom %,oxygen of from 55 atom % to 65 atom %, nitrogen of from 1 atom % to 20atom %, and hydrogen of from 0.1 atom % to 10 atom %. A silicon nitrideoxide (SiNO) film denotes a silicon nitride oxide film including Si offrom 25 atom % to 35 atom %, oxygen of from 15 atom % to 30 atom %,nitrogen of from 20 atom % to 35 atom %, and hydrogen of from 15 atom %to 25 atom %.

The hydrophobic surface may be formed by nitrogen plasma treatment orfluorine plasma treatment with a non-depositional gas. As for thenon-depositional gas, N₂O, N₂, NH₃, F₂, CF₄, or SiF₄ can be used.

An organic insulating film 812 that is an interlayer film and is made ofan organic insulating material is formed on the second insulating film811. As the organic insulating film 812, a film comprising one kind ofor plural kinds of organic resin materials selected from acrylic resin,polyamide, or polyimide of photosensitive or nonphotosensitive, forexample, can be used. In this example, positive photosensitive acrylicfilm having film thickness of 1.6 μm is formed. However, the filmthickness may be determined appropriately in the range of from 1 μm to 2μm. Thereafter, a passivation film comprising a nitride insulating film(typically, a silicon nitride film, a silicon nitride oxide film, or acarbon nitride film (CN)) may be formed on the organic insulating film812.

Thus, the present invention prevents film peeling by forming aninsulating film having a hydrophobic surface below an organic insulatingfilm to be used as an interlayer film to improve the adhesiveness ofthese films. Therefore, according to the present invention, asemiconductor device with high reliability can be manufactured with highyield.

Subsequently, a metal film is formed and etched to form a sourceelectrode, a drain electrode, and each wiring (not shown) forelectrically connecting to each impurity region. A film comprising anelement of aluminum (Al), titanium (Ti), molybdenum (Mo), tungsten (W),or silicon (Si), or an alloy film with the use of these elements may beused for the metal film. In this example, after laminating a titaniumfilm/a titanium-aluminum alloy film/a titanium film (Ti/Al—Si/Ti) to be100 nm/350 nm/100 nm in thickness respectively, a source electrode, adrain electrode 815 and each wiring (not shown) are formed by patterningand etching the laminated film into a desired shape.

Then, an electrode (an anode or a cathode in an EL display device or apixel electrode in a liquid crystal display device) is formed. For theelectrode, a transparent conductive film such as ITO and SnO₂ or a metalfilm such as Al in the case of a reflective liquid crystal displaydevice may be used. In this example, an electrode 817 is formed byforming ITO and etching the ITO into a desired shape.

According to the above-described steps, an active matrix substratecomprising a bottom gate TFT is completed.

EXAMPLE 4

In this example, an example of manufacturing a display device using anactive matrix substrate described in Example 1 as a semiconductor deviceof the present invention is described. The display device includes adisplay panel in which a light-emitting device formed on a substrate issealed with a covering material, and a display module comprising thedisplay panel provided with a TFT. The light-emitting device includes alayer having an organic compound providing electro luminescencegenerated by being applied with an electric field (a light-emittinglayer), an anode layer, and a cathode layer. The luminescence of theorganic compound includes light emission (fluorescence) generated whenrestoring from a singlet excitation state to the ground state, and lightemission (phosphorescence) when restoring from a triplet excitationstate to the ground state. An EL material which can be used in thepresent invention includes all luminescent materials emitting light byeither or both the singlet excitation and the triplet excitation.

In the present invention, all layers formed between the anode and thecathode in the light-emitting device are defined as an organiclight-emitting layer. The organic light-emitting layer specificallyincludes a light-emitting layer, a hole injection layer, an electroninjection layer, a hole transport layer, an electron transport layer,and the like. Basically, the light-emitting device has a laminatedstructure in order of an anode layer, a light-emitting layer, and acathode layer. As well as the structure, the light-emitting device mayhave such structure in which an anode layer, a hole injection layer, alight-emitting layer, and a cathode layer, or an anode layer, a holeinjection layer, a light-emitting layer, an electron transport layer,and a cathode layer are laminated in order.

FIG. 6 is a cross-sectional view of a semiconductor device of thisexample. In FIG. 6, a drive circuit provided over a substrate 900 isformed by using a CMOS circuit of FIG. 5. Thus, description of astructure may be referred to the description of an n-channel TFT and ap-channel TFT. In this example, a single gate structure is described;however, a double gate structure or a triple gate structure may beadopted.

An n-channel TFT and a p-channel TFT of a pixel region are also formedby using the n-channel TFT and the p-channel TFT in FIG. 5. Therefore, adescription of a structure may be referred to the description of then-channel TFT and the p-channel TFT in FIG. 5. In this example, a singlegate structure is shown; however, a double gate structure or a triplegate structure may be adopted.

Reference numeral 901 denotes an electrode that is superposed on thepixel electrode 911, thereby electrically connecting to a pixelelectrode 911 of a current control TFT.

Reference numeral 911 denotes a pixel electrode comprising a transparentconductive film (an anode of a light-emitting device). A compound ofindium oxide with tin oxide, a compound of indium oxide with zinc oxide,zinc oxide, tin oxide, or indium oxide can be used for the transparentconductive film. A film formed by adding gallium to the transparentconductive film may be used. The pixel electrode 911 may be formed on aflat interlayer insulating film before forming the above-describedelectrode. At this time, in the case of using an organic insulating filmcomprising an organic resin or the like as in the present invention, adefect such as film peeling can be prevented by making a base film havea hydrophobic surface to improve adhesiveness. This can be appliedsimilarly to a bank 912 described below. It is effective to planarize astep due to a TFT by using a planarizing film comprising resin. Since alight-emitting layer to be formed later is very thin, the step may causea defect in light emission. Consequently, the planarization ispreferably performed before forming the pixel electrode so as to formthe light-emitting layer on a surface as smooth as possible.

A bank 912 is formed after forming the electrode 901. The bank 912 maybe formed by patterning an insulating film or an organic resin filmincluding silicon of from 100 nm to 400 nm.

Since the bank 912 is an insulating film, electrostatic discharge damageto a device in deposition needs attention. In this example, theresistivity is reduced by adding a carbon particle or a metal particleinto an insulating film to be a material of the bank, therebysuppressing generation of static electricity. At this time, the amountof a carbon particle or a metal particle to be added may be adjusted inorder for the resistivity to be from 1×10⁶ Ωm to 1×10¹² Ωm (preferablyfrom 1×10⁸ Ωm to 1×10¹⁰ Ωm).

A light-emitting layer 913 is formed on the pixel electrode 911. Onlyone pixel is shown in FIG. 6; however, in this example, light-emittinglayers corresponding to respective colors of R (red), G (green), and B(blue) are formed separately. In this example, a low molecular weightorganic light-emitting material is formed by vapor deposition.Specifically, the light-emitting layer has a laminate structure having acopper phthalocyanine (CuPc) film provided with a thickness of 20 nm asthe hole injection layer and a tris-8-quinolinolato aluminum complex(Alq₃) film provided thereupon with a thickness of 70 nm as thelight-emitting layer. Color of emission light can be controlled byadding fluorescent dye such as quinacridone, perylene, or DCM 1 to Alq₃.

However, the foregoing example is an example of the organiclight-emitting material to be used for the light-emitting layer and theorganic light-emitting material is not necessarily limited thereto. Thelight-emitting layer (layer for light emission and for carrier movementfor the light emission) may be formed by freely combining thelight-emitting layer, the charge transport layer, and the chargeinjection layer. For example, although the example in which the lowmolecular weight organic light-emitting material is used for thelight-emitting layer is described in this example, an intermediatemolecular weight organic light-emitting material or a high molecularweight organic light-emitting material may be used in place. In thepresent invention, an organic light-emitting material which does notsublimate and has molecularity of equal to or less than 20 or amolecular chain length of equal to or less than 10 μm is defined as theintermediate molecular weight organic light-emitting material. Inaddition, as an example of using the high molecular weight organiclight-emitting material, a laminate structure having a polythiophene(PEDOT) film provided by spin coating with a thickness of 20 nm as thehole injection layer and a paraphenylene-vinylene (PPV) film with athickness of approximately 100 nm provided thereupon as thelight-emitting layer may be given. In addition, emission wavelength canbe selected from red through blue by using π-conjugated polymer of PPV.An inorganic material such as silicon carbide can be used for the chargetransport layer and the charge injection layer. These organiclight-emitting materials and inorganic materials are formed by usingknown materials.

Next, a cathode 914 comprising a conductive film is provided on thelight-emitting film 913. In this example, an alloy film of aluminum andlithium is used as the conductive film. A known MgAg film (alloy film ofmagnesium and silver) may be used alternatively. A conductive filmcomprising an element belonging to Group 1 or 2 of the periodic table ora conductive film added with the elements may be used as a cathodematerial.

A light-emitting device 915 is completed at the time of forming up tothe cathode 914. The light-emitting device 915 herein refers to a diodeformed with the pixel electrode (anode) 911, the light-emitting layer913, and the cathode 914.

It is effective to provide a passivation film (not shown) so as tocompletely cover the light-emitting device 915. The passivation film ismade of an insulating film including a carbon film, a silicon nitridefilm, a carbon nitride film (CN), or a silicon nitride oxide film, andthe insulating film is used in a single layer or a combined lamination.

In such the case, a film favorable in coverage is preferably used as thepassivation film. It is effective to use a carbon film, particularly aDLC film. Since the DLC film can be formed in a temperature range offrom room temperature to equal to or less than 100° C., the DLC film canbe easily formed over the light-emitting layer 913 having low heatresistance. The DLC film has a high blocking effect to oxygen and cansuppress oxidization of the light-emitting layer 913. Consequently, aproblem of oxidation of the light-emitting layer 913 during thefollowing sealing step can be avoided.

Furthermore, a sealing material 917 is provided on the passivation film(not shown) to bond a covering material 918. An ultraviolet curableresin may be used for the sealing material 917. It is effective toprovide a substance having a hygroscopic effect or an antioxidant effectinside. In addition, in this example, carbon films (preferably DLCfilms) are formed on both sides of a glass substrate, a quartzsubstrate, a plastic substrate (including a plastic film), or a flexiblesubstrate, thereby obtaining the covering material 918. An aluminum film(AlON, AlN, AlO, or the like), SiN, or the like can be used as well asthe carbon film.

Thus, a semiconductor device having a structure as shown in FIG. 6 iscompleted. It is effective to continuously carry out the steps of up toforming the passivation film (not shown) after forming the bank by usinga deposition apparatus of a multi-chamber system (or an in-line system)without exposure to the atmosphere. In addition, with furtherdevelopment, the steps of up to sealing with the covering material 918can be carried out without exposure to the atmosphere.

By providing an impurity region overlapping a gate electrode with aninsulating film therebetween, an n-channel TFT resistive todeterioration resulting from a hot-carrier effect can be formed.Consequently, a semiconductor device with high reliability can berealized.

In addition, in this example, only a structure of a pixel portion and adrive circuit is shown. However, according to the manufacturing steps inthis example, logic circuits such as a signal division circuit, a D/Aconverter, an operation amplifier, and a γ-correction circuit also canbe formed on the same insulator. Furthermore, a memory or amicroprocessor can be formed thereon.

The present invention prevents a defect such as film peeling by forminga film having a hydrophobic surface below an organic insulating film tobe used as an interlayer film to improve the adhesiveness of thesefilms. Therefore, according to the present invention, a semiconductordevice with high reliability can be manufactured with high yield.

EXAMPLE 5

Various semiconductor devices can be manufactured by applying thepresent invention. Namely, the present invention can be applied tovarious electronics in which the semiconductor devices are respectivelymounted. Moreover, reliability of the electronics can be improved byapplying the present invention.

The following can be given as such electronics: a video camera; adigital camera; a projector; a head mounted display (a goggle typedisplay); a car navigation system; a car stereo; a personal computer; amobile information terminal (a mobile computer, a cellular phone, or anelectronic book); and the like. Examples of the electronics are shown inFIGS. 7A to 7F, 8A to 8D, and 9A to 9C.

FIG. 7A is a personal computer including a main body 3001, an imageinput portion 3002, a display portion 3003, and a keyboard 3004, and thelike. The personal computer of the present invention is completed byapplying the present invention to the display portion 3003.

FIG. 7B is a video camera including a main body 3101, a display portion3102, a voice input portion 3103, operation switches 3104, a battery3105, an image receiving portion 3106, and the like. The video camera ofthe present invention is completed by applying the present invention tothe display portion 3102.

FIG. 7C is a mobile computer including a main body 3201, a camerasection 3202, an image receiving portion 3203, an operation switch 3204,a display portion 3205, and the like. The mobile computer of the presentinvention is completed by applying the present invention to the displayportion 3205.

FIG. 7D is a goggle type display including a main body 3301, a displayportion 3302, an arm portion 3303, and the like. A flexible substrate isused as a substrate for the display portion 3302, and the goggle typedisplay is manufactured by making the display portion 3302 curved. Alightweight and thin goggle type display is realized. The goggle typedisplay of the present invention is completed by applying the presentinvention to the display portion 3302.

FIG. 7E is a player using a recording medium recording a program(hereinafter, referred to as a recording medium) which includes a mainbody 3401, a display portion 3402, a speaker portion 3403, a recordingmedium 3404, operation switches 3405, and the like. The player uses aDVD (digital versatile disc), a CD, and the like as the recordingmedium, and can be used for music appreciation, film appreciation,games, and Internet. The recording medium of the present invention iscompleted by applying the present invention to the display portion 3402.

FIG. 7F is a digital camera including a main body 3501, a displayportion 3502, a view finder 3503, operation switches 3504, an imagereceiving portion (not shown), and the like. The digital camera of thepresent invention is completed by applying the present invention to thedisplay portion 3502.

FIG. 8A is a front type projector including a projection apparatus 3601,a screen 3602, and the like. The front type projector of the presentinvention is completed by applying the present invention to a liquidcrystal display device 3808 constituting a part of the projectionapparatus 3601 and to other drive circuits.

FIG. 8B is a rear type projector including a main body 3701, aprojection apparatus 3702, a mirror 3703, a screen 3704, and the like.The rear type projector of the present invention is completed byapplying the present invention to the liquid crystal display device 3808constituting a part of the projection apparatus 3702 and to other drivecircuits.

FIG. 8C shows an example of structures of the projection apparatuses3601 and 3702 respectively in FIGS. 8A and 8B. Each of the projectionapparatuses 3601 and 3702 comprise a light source optical system 3801,mirrors 3802 and 3804 to 3806, a dichroic mirror 3803, a prism 3807, aliquid crystal display device 3808, a retardation plate 3809, and aprojection optical system 3810. The projection optical system 3810comprises an optical system including a projection lens. Though thisexample shows an example of a three-plate type, there is no particularlimitation thereto, and a single-plate type may be used for instance.Further, an optical system such as an optical lens, a film having afunction of polarizing light, a film for adjusting a phase difference,an IR film, or the like may be appropriately disposed in an optical pathshown by an arrow in FIG. 8C.

FIG. 8D shows an example of a structure of the light source opticalsystem 3801 in FIG. 8C. In this example, the light source optical system3801 comprises a reflector 3811, a light source 3812, lens arrays 3813and 3814, a polarizing conversion device 3815, and a condenser lens3816. Note that the light source optical system shown in FIG. 8D ismerely an example and the structure is not particularly limited thereto.For instance, an optical system such as an optical lens, a film having afunction of polarizing light, a film for adjusting a phase difference,an IR film, or the like may be appropriately disposed in the lightsource optical system.

Note that a transmission type electro-optical apparatus is used in thecase of the projectors shown in FIGS. 8A to 8D, and examples of applyinga reflection type electro-optical device and a display device are notshown in the figures.

FIG. 9A is a cellular phone including a main body 3901, a voice outputportion 3902, a voice input portion 3903, a display portion 3904,operation switches 3905, an antenna 3906, and the like. The cellularphone of the present invention is completed by applying the presentinvention to the display portion 3904.

FIG. 9B is a portable book (electronic book) including a main body 4001,display portions 4002 and 4003, a recording medium 4004, operationswitches 4005, an antenna 4006, and the like. The mobile book of thepresent invention is completed by applying the present invention to thedisplay portions 4002 and 4003.

FIG. 9C is a display including a main body 4101, a supporting section4102, a display portion 4103, and the like. The display portion 4103 ismanufactured by using a flexible substrate, thereby realizing alightweight and thin display. In addition, the display portion can bemade curved. The display of the present invention is completed byapplying the present invention to the display portion 4103.

As described above, the present invention can be fairly widely appliedto electronics in various fields.

This application is based on Japanese Patent Application serial no.2003-089660 filed in Japan Patent Office on Mar. 28 in 2003, thecontents of which are hereby incorporated by reference.

TABLE 1 base film SiN SiNO sample SiN(a) SiN(b) SiN(c) SiNO(a) SiNO(b)SiNO(c) hydrofluoric acid treatment (120 sec) ∘ ∘ hydro washing (60 sec)∘ ∘ hydrofluoric acid treatment (120 sec) ∘ ∘ water washing ∘ ∘heat-treatment (150° C., 3 min) ∘ ∘ applying a positive photosensitiveacrylic resin ∘ ∘ washing periphery of sample ∘ ∘ exposure ∘ ∘development ∘ ∘ water contact angle (degree)(after deposition) 50 44wettability of the positive photosensitive acrylic resin (afterapplying) ∘ ∘ ∘ ∘ ∘ ∘ adhesiveness of patterns (after development) ∘ ∘ ∘x x ∘

TABLE 2 base film SiON SiO₂ sample SiON(a) SiON(b) SiON(c) SiO₂(a)SiO₂(b) SiO₂(c) hydrofluoric acid treatment (120 sec) ∘ ∘ hydro washing(60 sec) ∘ ∘ hydrofluoric acid treatment (120 sec) ∘ ∘ water washing ∘ ∘heat-treatment (150° C., 3 min) ∘ ∘ applying a positive photosensitiveacrylic resin ∘ ∘ washing periphery of sample ∘ ∘ exposure ∘ ∘development ∘ ∘ water contact angle (degree)(after deposition) 24 15wettabiity of the positive photosensitive acrylic resin (after applying)∘ ∘ ∘ ∘ ∘ ∘ adhesiveness of patterns (after development) x x x x x x

What is claimed is:
 1. A method for manufacturing a semiconductordevice, comprising the steps of: forming a gate insulating film over asemiconductor film; forming a gate electrode over the gate insulatingfilm; forming a first inorganic insulating film containing hydrogen overthe gate electrode; reducing a hydrogen content in the first inorganicinsulating film by heat-treating the first inorganic insulating film;after the step of reducing the hydrogen content in the first inorganicinsulating film, forming a second inorganic insulating film includingsilicon and nitrogen on and in contact with the first inorganicinsulating film; and forming an organic insulating film on and incontact with the second inorganic insulating film, wherein a hydrogenconcentration in the second inorganic insulating film is higher than ahydrogen concentration in the first inorganic insulating film.
 2. Amethod for manufacturing a semiconductor device according to claim 1,wherein the first inorganic insulating film and the second inorganicinsulating film are a nitride.
 3. A method for manufacturing asemiconductor device according to claim 1, wherein the second inorganicinsulating film has a larger contact angle of water than the firstinorganic insulating film.
 4. A method for manufacturing a semiconductordevice according to claim 1, wherein the organic insulating film isformed of a photosensitive organic insulating film.
 5. A method formanufacturing a semiconductor device according to claim 1, wherein thesecond inorganic insulating film is formed to have a contact angle ofwater of equal to or more than 30° .
 6. A method for manufacturing asemiconductor device, comprising the steps of: forming a gate insulatingfilm over a semiconductor film; forming a gate electrode over the gateinsulating film; forming a first inorganic insulating film over the gateelectrode; heat-treating the first inorganic insulating film; after thestep of heat-treating the first inorganic insulating film, forming asecond inorganic insulating film including silicon and nitrogen on andin contact with the first inorganic insulating film; and forming anorganic insulating film on and in contact with the second inorganicinsulating film, wherein a hydrogen concentration in the secondinorganic insulating film is higher than a hydrogen concentration in thefirst inorganic insulating film, wherein the first inorganic insulatingfilm and the second inorganic insulating film are a nitride.
 7. A methodfor manufacturing a semiconductor device according to claim 6, whereinthe second inorganic insulating film has a larger contact angle of waterthan the first inorganic insulating film.
 8. A method for manufacturinga semiconductor device according to claim 6, wherein the secondinorganic insulating film is formed to have a contact angle of water ofequal to or more than 40° .
 9. A method for manufacturing asemiconductor device according to claim 6, wherein the organicinsulating film is formed to include one of or a plurality of organicresin materials selected from acrylic resin, polyamide, or polyimide ofphotosensitive or nonphotosensitive.
 10. A method for manufacturing asemiconductor device according to claim 6, further comprising: forming asource electrode and a drain electrode which are connected to thesemiconductor film after the formation of the organic insulating film;and forming an electrode which is connected to one of the sourceelectrode and the drain electrode and functions as a pixel electrode.11. A method for manufacturing a semiconductor device according to claim1, wherein the first inorganic insulating film comprises silicon oxide.12. A method for manufacturing a semiconductor device according to claim1, wherein the first inorganic insulating film comprises silicon, oxygenand nitrogen where a content of oxygen is larger than a content ofnitrogen.
 13. A method for manufacturing a semiconductor deviceaccording to claim 1, wherein the second inorganic insulating filmcomprises silicon nitride.
 14. A method for manufacturing asemiconductor device according to claim 1, wherein the second inorganicinsulating film comprises silicon, oxygen and nitrogen where a contentof nitrogen is larger than a content of oxygen.
 15. A method formanufacturing a semiconductor device according to claim 1, wherein theheat-treatment of the first inorganic insulating film is performed at300° C. to 550° C.
 16. A method for manufacturing a semiconductordevice, comprising the steps of: forming a first inorganic insulatingfilm containing hydrogen over a semiconductor layer; reducing a hydrogencontent in the first inorganic insulating film by heat-treating thefirst inorganic insulating film; after the step of reducing the hydrogencontent in the first inorganic insulating film, forming a secondinorganic insulating film including silicon and nitrogen on and incontact with the first inorganic insulating film; and forming an organicinsulating film on and in contact with the second inorganic insulatingfilm, wherein a hydrogen concentration in the second inorganicinsulating film is higher than a hydrogen concentration in the firstinorganic insulating film.
 17. A method for manufacturing asemiconductor device according to claim 16, wherein the heat-treatmentof the first inorganic insulating film is performed at 300° C. to 550°C.
 18. A method for manufacturing a semiconductor device according toclaim 16, wherein the second inorganic insulating film has a largercontact angle of water than the first inorganic insulating film.
 19. Amethod for manufacturing a semiconductor device according to claim 16,wherein the organic insulating film is formed of a photosensitiveorganic insulating film.
 20. A method for manufacturing a semiconductordevice according to claim 16, wherein the second inorganic insulatingfilm is formed to have a contact angle of water of equal to or more than30° .
 21. A method for manufacturing a semiconductor device according toclaim 16, wherein the first inorganic insulating film comprises silicon,oxygen and nitrogen where a content of oxygen is larger than a contentof nitrogen.
 22. A method for manufacturing a semiconductor deviceaccording to claim 16, wherein the second inorganic insulating filmcomprises silicon nitride.
 23. A method for manufacturing asemiconductor device according to claim 16, wherein the second inorganicinsulating film comprises silicon, oxygen and nitrogen where a contentof nitrogen is larger than a content of oxygen.
 24. A method formanufacturing a semiconductor device according to claim 16, wherein thesemiconductor layer comprises silicon.